Seed treatment technology

And what do seed treatment products consist of? The most important thing, of course, is the active ingredient which is responsible for the fungicidal and/or insecticidal effect. Yet a seed treatment product contains many other components too, the most important of which are adhesive substances (to make the active ingredient stick to surface of the seed), dispersion substances (to allow for even distribution of the active ingredient), and colorants (so that it can be seen immediately whether or not even distribution of the seed dressing has been achieved).

These and other important properties such as seed flowability are supported and complemented by the co-application of a proper film coating designed for a specific seed treatment product.

Modern Techniques

Nowadays, modern seed treatment machines have been designed to a high standard for treatment of large quantities of seed . However, different seed treatment formulations and different seeds sometimes require different machines.

The most common seed treatment formulations worldwide are flowable concentrates, wettable powders and liquids.

Advanced seed dressing methods include film coating and pelleting.

Bayer CropScience’s most recent development is water-borne coatings, seed treatments in the form of a water-based suspension which are particularly user-friendly. They generate neither dust nor solvent vapors during use, and machines and equipment are easy to clean with just water.




Main Application Methods

	Seed Dressing: Application using simple application machinery,
	Film Coating: Film coatings are applied together with the insecticidal and/or fungicidal seed treatment product to improve the application quality. Proper film coatings applied at the correct use rate reduce abrasion, dust formation and hence the loss of active ingredient during application, packaging and sowing. They improve the even distribution of the seed treatment products on the seeds and restore good seed flowability/sowability. Film coatings are part of professional seed treatment for field crops and vegetables, and are applied mainly by professional seed companies. In order to confer all the technical properties such as reduced abrasion and dust formation, good flowability, and improved seed coverage and coloration, modern film coatings are quite complex and sophisticated products which contain polymers, loading materials and wetting and stability agents in combination with pigments and shine agents. The combination of these components and the exact recipe strongly depend on the detailed requirements, the crop and the seed treatment product used. In addition, film coatings must not hinder water uptake by the seeds, their germination or field emergence. Film coatings form a very thin film and do not change the size, shape or weight of the seeds.
	Pelleting: Pelleting has two main purposes. One is to give seeds with an uneven surface a uniform and homogeneous size and shape, e.g. for sugar beets and fodder beets. The second purpose of pelleting is to increase the size and/or weight of very small seeds such as vegetable or grass seeds. In both cases the intention is to adapt and change the shape, size and/or weight of the seeds to allow precision sowing with modern equipment. The inert materials used for the pelleting process must be capable of forming a robust and stable pellet but at the same time must not hinder water uptake by the seeds and hence germination and emergence. Seed treatment products are usually applied to pelleted seeds in a second step and always in combination with a film coating.
	Pelleting and Coating: The term describes the sequential application of different film coatings in combination with different seed treatment products. It can be used with either pelleted or non-pelleted seeds.
	Multilayer Coating: A highly sophisticated method allowing sequential application of multilayer materials, including the incorporation of fungicides and insecticides.

	Giving Seeds a Film Coating Film coating products contain polymers, dyes and surfactants and form a fine air- and water-permeable film that improves the distribution and retention of crop protection agents on the seed surface. The coating products contribute to a significant reduction of the amount of dust released during the application of the crop protection agents to the seed and during handling and use of the treated seed on the farm. This means the operator is better protected. The film coating also improves the flowability of the seed, i.e. the ability of seed to flow instead of clumping in the treatment station or sower, which means easier production on an industrial scale. Film coating also allows sowing rates to be managed accurately. The coloration of the coating gives the seed an attractive, glossy appearance, but also has the practical use of allowing differentiation between varieties and between different types of treatment. Film coatings do not significantly modify the shape and weight of the seed.

	Pelleting for Uniform Sizes and Shape Surrounding a seed with a thick coat, the pelleting process is designed to make seeds uniform in size, shape and weight so that they can be precision-sown with modern drilling machinery. The other advantage of pelleting is the additional protection it provides to the seed. The pelleting material must be robust enough to remain in place during handling, transport and sowing. Pelleting guarantees that the active ingredients are distributed evenly among individual seeds within a seed lot. The application of a covering layer of fungicide and/or insecticide ensures that exactly the right dose is available at the right time. The covering layer is designed to break open after sowing, so that it doesn’t hinder seed germination.